Scalable video coding and decoding methods, and scalable video encoder and decoder

Abstract

Scalable video coding and decoding methods, a scalable video encoder, and a scalable video decoder. The scalable video coding method includes receiving a GOP, performing temporal filtering and spatial transformation thereon, quantizing and generating a bitstream. The scalable video encoder for performing the scalable video coding method includes a weight determination block which determines a weight for scaling. The scalable video decoding method includes dequantizing the coded image information obtained from a received bitstream, performing descaling, inverse spatial transformation, and inverse temporal filtering on the scaled transform coefficients, thereby recovering video frames. The scalable video decoder for performing the scalable video decoding method includes an inverse weighting block. The standard deviation of Peak Signal to Noise Ratios (PSNRs) of frames included in a group of pictures (GOP) is reduced so that video coding performance can be increased.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to video compression, and more particularly, to scalable video coding and decoding methods using a weight, and an encoder and a decoder using the methods, respectively. 2. Description of the Related Art With the development of information communication technology including the Internet, video communication as well as text and voice communication has increased. Conventional text communication cannot satisfy the various demands of users, and thus demand for multimedia services that can provide various types of information such as text, pictures, and music have increased. Multimedia data requires a large capacity storage medium and a wide bandwidth for transmission since the amount of multimedia data is usually large. For example, a 24-bit true color image having a resolution of 640*480 needs a capacity of 640*480*24 bits, i.e., data of about 7.37 Mbits, per frame. When this image is transmitted at...

AI Technical Summary

Benefits of technology

The present invention provides scalable video coding and decoding methods allowing changes in Peak Signal to Noise Ratio (PSNR) to be decreased, and a scalable video encoder and decoder therefor.

The spatial transform block may perform wavelet transformation on the video frames to remove the spatial redundancy from the video frames, the temporal filtering block may generate transform coefficients using subbands obtained by performing the MCTF on the wavelet transformed video frames, and the weight determination block may determine the weight using the wavelet transformed frames and multiply the determined weight by transform coefficients that are obtained from some subbands, thereby obtaining the scaled transform coefficients.

According to still another aspect of the present invention, there is provided a scalable video decoding method comprising extracting coded image information, coding order information, and weight information from a bitstream, obtaining scaled transform coefficients by dequantizing the coded image information, and performing descaling, inverse spatial transformation, and inverse temporal filtering on the scaled transform coefficients in a decoding order reverse to a coding order indicated by the coding order information, thereby recovering video frames.

Problems solved by technology

Conventional text communication cannot satisfy the various demands of users, and thus demand for multimedia services that can provide various types of information such as text, pictures, and music have increased.

Multimedia data requires a large capacity storage medium and a wide bandwidth for transmission since the amount of multimedia data is usually large.

These methods have satisfactory compression rates, but they do not have the flexibility of a truly scalable bitstream since they use a reflexive approach in a main algorithm.

However, conventional IWVC has lower performance than a coding method such as H.264.

Due to this lower performance, IWVC is used only for very limited applications although it has very excellent scalability.

Accordingly, it has been an issue to improve the performance of data coding methods having scalability.

Although conventional IWVC has excellent scalability, it still has disadvantages.

When picture quality varies greatly temporarily, people perceive that picture quality is degraded.

As described above, differences in picture quality impede commercial services such as streaming services.

Images